1. Field of the Invention
The present invention generally relates to a disk unit, and more particularly, to a disk unit included as a CD-ROM driving apparatus in a notebook-type personal computer, etc.
2. Description of the Related Art
For a storage medium storing information such as a data base and software, a compact disk (CD: 12-cm and 8-cm diameters) from which data is read out using a laser-type pick-up is being used. Therefore, to enable the compact disk to be included in a notebook-type personal computer, etc., a built-in disk unit (CD-ROM driving apparatus) which can easily be built in a chassis is being developed.
In a prior-art disk unit, a tray on which a disk is set is driven by a motor. When the tray is moved outside the chassis of the disk unit, the disk is set on a turn table in the tray, and the tray is returned to the chassis by a driving torque of the motor.
Therefore, in the above-discussed method of driving the tray by the motor, the motor driving the tray and a transmission mechanism transmitting the driving torque to the tray are required. Accordingly, it is difficult to miniaturize and reduce thickness of the disk unit, and, thus, the disk unit could not have been included in the notebook-type personal computer.
To resolve the above problem, a disk unit that does not use the above-discussed motor and transmission mechanism has been developed. The disk unit has a mechanism in which the tray is moved to a disk-driving position in the chassis, and is moved to a disk-exchanging position outside the chassis by a manual operation.
FIG. 1 shows a configuration example of the prior-art disk unit without using the motor and the driving-torque transmission mechanism. This drawing shows a disk unit 100 in a condition in which a tray 102 is extracted from a chassis 101 to a disk-exchanging position. The disk unit 100 has a mechanism in which by a manual operation, the tray 102 is extracted to the disk-exchanging position outside the chassis. Therefore, guide-rail mechanisms 103, 104 for extracting the tray 102 from the chassis 101 are provided in the disk unit 100.
The guide-rail mechanisms 103, 104 are constructed with a moving-side rail 105 (shown in one side of the tray 102) provided in both sides of the tray 102, a fixed-side rail 106 (shown in one side of the chassis 101) which is extended in parallel with the moving-side rail 105 and fixed to both side walls 101a of the chassis 101, slide rails 107, 108 which are provided between the moving-side rail 105 and the fixed-side rail 106 and are jointed with the both rails 105, 106 in a slidable form.
When the tray 102 is extracted from the chassis 101, the fixed-side rail 106 slides in an extraction direction along the slide rails 107, 108, and also, the slide rails 107, 108 slide in the extraction direction along the moving-side rail 105.
In this way, in the guide-rail mechanisms 103, 104, the slide rails 107, 108 provided between the fixed-side rail 106 and the moving-side rail 105 are connected with the fixed-side rail 106 and the moving-side rail 105 in the slidable form. Therefore, the moving-side rail 105 may move by a stroke substantially twice the sliding distance of the slide ails 107, 108. Accordingly, as shown in FIG. 1, the tray 102 can extend to be extracted from the chassis 101, and, thus, a disc-exchanging operation in the tray 102 may easily be carried out. In this case, as the extended part of the tray 102, extending from the chassis 101 increases, the disc-exchanging operation in the tray 102 is much easier.
However, in the structure in which the tray 102 is extended from the chassis 101 using the guide-rail mechanisms 103, 104, when the tray 102 is extended to a given disk-exchanging position, to prevent the tray 102 from being further extracted from the given disk-exchanging position, a slide-stopping mechanism needs to be provided.
FIG. 2 shows a prior-art slide-stopping mechanism. The slide-stopping mechanism shown in FIG. 2 is constructed with a slide stopper 109 provided on a bottom face of the chassis 101, and a sliding piece 110 formed in a back-end part of the moving-side rail 105. When the moving-side rail 105 slides in a forward direction (in the right direction of the drawing) with an extracting operation of the tray 102, the sliding piece 110 also slides in the forward direction. When the sliding piece 110 contacts the slide stopper 109, the sliding operation of the tray 102 is restricted.
Therefore, in the prior-art slide-stopping mechanism, since the sliding piece 110 is provided in the back-end part of the moving-side rail 105, the length of the extended part of the tray 102 is determined by a length of the moving-side rail 105. Accordingly, the tray 102 can not be moved to a position in which the disk-exchanging operation may easily be carried out. There is thus a problem in that the disk-exchanging operation may not easily be carried out.